1. Field of the Invention
The present invention relates to a mobile radio communication apparatus capable to a plurality of radio communication systems.
2. Description of the Related Art
Currently, along with the tremendous popularization of radio communication systems, a plurality of radio communication systems with different standards are being in use. Generally, mobile radio communication apparatuses are prepared for the respective mobile radio communication systems. Recent mobile radio communication apparatuses are required to be able to cope with not only conventional speech communications but also various application services such as e-mail, data communication, and Web (world wide web) browsing. Hence, a strong demand has arisen for a so-called single multimode terminal apparatus which can cope with a plurality of radio communication systems and various application services.
As a technique for implementing a multimode terminal apparatus, a SDR (Software Defined Radio) has been proposed. The SDR realizes at least some of signal processing operations necessary for transmission/reception by software processing using a programmable device such as a DSP (Digital Signal Processor). A SDR unit can cope with various radio communication systems or various application services by exchanging software. For example, speech communication can be shifted to data communication. Alternatively, a radio communication system can be handed off from the W-CDMA scheme to the cdma 2000 scheme. The basic idea of such the SDR is presented by, e.g., Jpn. Pat. Appln. KOKAI Publication No. 9-331579. However, how to implement the apparatus in consideration of various situations is not sufficiently disclosed in this prior art.
For example, for a radio communication system, the digital information transmission rate is being increased. Accordingly, the standard is also frequently changed. Every time the standard is changed, the SDR unit must be designed and developed. A section that handles a baseband signal in the SDR unit, i.e., a so-called modem section processes a large amount of data. In addition, required specifications including a processing delay are strict. For these reasons, the design of a modem section is changed every time the standard of a radio communication system is changed. The above-described programmable device can flexibly cope with such a change in design by changing software. However, a programmable device such as a DSP may be unable to sufficiently cope with high-speed processing of a broadband radio communication signal.
The SDR unit occupies many resources of a terminal apparatus to cope with various radio communication systems and application services by switching software. To cope with a new radio communication system or to add an application service function, a free resource must be prepared. A resource management that optimally distributes one resource to a radio communication system or communication service is also required. Especially, a mobile radio communication apparatus for mobile communication is required to be compact and to save power consumption. Since the resource amount is restricted, resource management is important. A resource means a processor such as a CPU or DSP, hardware such as a memory or a RAM (Random Access Memory), the processing capability of a processor, or the like.
With a general design concept of a mobile radio communication apparatus, resources are permanently assigned to a plurality of signal processing operations. When this concept is applied to the SDR unit, the resource utilization efficiency greatly decreases because the wireless unit must cope with a plurality of radio communication systems or a plurality of application services. Resource management for a computer is mainly specialized to memory areas. Resource management based on a hardware space or resource management according to a wireless quality is not taken into consideration.
In the SDR unit, a software module is downloaded through a communication channel and stored in a storage device, as described in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 9-331579. When software module download is repeated to make the SDR unit to cope with a new communication service, the amount of modules stored in the storage device increases. The capacity of the storage device in the SDR unit is finite. Practically, at the time of download, unnecessary modules must be deleted from already stored modules. To cope with a new version of a module, updating a module stored in the storage device must also taken into consideration. In deleting updating a module, it is inefficient to refer to the name or version of each module in the storage device to determine a module to be deleted or updated. A mechanism which efficiently manages modules is demanded to be implemented.
In various applications described above, which can be processed by the SDR unit, generally, a list of Web pages to be browsed by the user of the SDR unit or a list of telephone numbers and e-mail addresses of specific communication partners of the user is displayed on a menu. However, in the SDR unit capable of coping with a plurality of radio communication systems, generally, when an adapted radio communication system is changed, such list files cannot be used. Each radio communication system provides unique application services established by a communication service company that operates the system. This system also provides a browser and mail system having unique specifications.
The specifications of application services change depending on the radio communication system. Hence, a list file of Web pages or telephone numbers and mail addresses must be prepared for each radio communication system. This is because an application service unique to a radio communication system uses a file format unique to the application service. For this reason, in the SDR unit, a list file of Web pages or telephone numbers and mail addresses described in a file format corresponding to a certain radio communication system cannot be used for another radio communication system. When the radio communication system to be used is changed, the user of the SDR unit must newly create a list file for an application service of the radio communication system. In addition, the user must independently manage list files for a plurality of potential radio communication systems.